1. Field of the Invention
This invention pertains to remote sensing for ground vehicles and, more particularly, to a technique for achieving a higher vantage point from which the sensing occurs.
2. Description of the Related Art
One significant challenge presented by unmanned, robotic vehicles is situational awareness. Situational awareness includes detection and identification of conditions in the surrounding environment. Robotic vehicles typically carry a variety of instruments to remotely sense the surrounding environment. Commonly used instruments include technologies such as:                acoustic;        infrared, such as short wave infrared (“SWIR”), long wavelength infrared (“LWIR”), and forward looking infrared (“FLIR”);        optical, such as laser detection and ranging (“LADAR”).Typically, several different instruments are used to employ more than one of these technologies since each has advantages and disadvantages relative to the others.        
A common limitation for any of these technologies is the vantage point of the instrument. For instance, the height of the vantage point inherently limits the field of view for any sensor, which is particularly problematical for long-range sensors. The height of the vantage point also affects the perspective of the data collected. For instance, the perspective afforded by a higher vantage point facilitates identifying negative obstacles (e.g., ditches) and cul-de-sacs.
One approach to this problem is to mount at least some of the sensors relatively high on the body of the vehicle. Sensors for which this limitation is particularly problematical are sometimes mounted to a mast extending upwardly from the vehicle. However, simply positioning the sensors high on the vehicle's body or on a sensor mast may offer only marginal improvement. Mounting sensors atop a mast may complicate maneuverability for the vehicle and or have other adverse consequences, such as increasing the vehicle's profile.
Another approach places the sensors on an airborne vehicle that communicates wirelessly with the ground vehicle. The airborne vehicle may be, for instance, a tele-operated or robotic helicopter that senses the environment and wirelessly transfers the data to the ground vehicle. This approach can greatly enlarge the field of view, since the altitude of the airborne vehicle is independent of the ground vehicle. However, this approach also manifests several drawbacks. For instance, because the airborne vehicle is independent of the ground vehicle, it must provide its own power, which adds size, weight, and complexity to the airborne vehicle. Also, since the airborne vehicle communicates wirelessly, precautions must be taken when several are used contemporaneously in the same general area. The independence of the airborne and ground vehicles also introduces uncertainties in the data caused by uncertainties in the relative positions of the vehicles.
The present invention is directed to resolving, or at least reducing, one or all of the problems mentioned above.